This invention relates generally to hand trucks, and more particularly, to clamping devices used on the hand trucks for securing loads thereon.
The problem of securing a load on a hand truck is well known in the art and has been addressed by many inventive devices. For example, the upper part of the load is usually secured by a belt, a bail, a hook or a claw, for example, and the lower part of the load is held by a load bearing platform. The upper load securing device is usually designed to fit a uniquely shaped load such as a barrel, a crate, etc. The load platform has also been designed for uniquely shaped loads. Although most of these devices have served the purpose for which designed, there exists a need for a universal load securing device that can be attached to hand trucks of standard design.
One particular device of wide use is the belt. This device is usually attached to the middle of the hand truck. One end of the belt is wrapped around a spring actuated drum so that an appropriate amount of the belt can be withdrawn to go around the load on the hand truck. The loose end of the belt is inserted in a pickup so that tension can be applied in the belt to securely hold the load to the back of the truck. Obviously, this device has many advantages but it is time consuming to pull the belt around the load and tighten it too. It is also time consuming to release the load quickly. This is true when many articles are to be moved. Further, a stacked load may not be properly held in place by the belt device because the belt will only secure items directly in contact with the belt. The belt device fails to exert force down on a load, only laterally.
Another device is a clamp. The clamp is placed on the top of the load. The problem with past clamping devices has been that they are designed to secure loads of unique shapes, and are usually an integral part of the hand truck operation.
Thus the need exists for a clamping device that exerts a downward force to secure the load, is easily operated by one man, is quickly applied and removed, and can be attached to standard trucks without extensive modifications.